AVR-Chat

I'm using a 168p on a project and I've run into a couple of things  
that I want to make sure I got right from the data sheet.

The first is using the ADC7 pin as an output.  Can that be done?  My  
compiler tells me the required defines are not there and all I see in  
the datasheet is about the pin being an ADC input pin.  Is that pin  
input only?

The other is when I use the PCINT pins.  Is there a way to tell which  
of the pins triggered the int or do I have to keep track of the pins  
state and compare it myself?  Again, I didn't see a register that I  
can just look at with that information..

I'd love to hear that I missed both of these things.

Thanks.